This invention relates to a device for displaying the level of a fluid contained in a tank. The device is applicable more particularly to displaying the fuel level in the tank of a two-wheeled vehicle such as a motorcycle, MOPED, motorized bicycle and the like.
In regard to two-wheel vehicles provided with a fuel tank sometimes referred to as a shell tank, a fuel-level measuring device based on the principle of communicating vessels has already been proposed. This known device consists of a transparent tube, outside the tank, extending over the entire height of the tank and in fluid communication with the bottom of the tank.
Under these conditions, the display liquid is the same liquid which is contained in the tank. It is consequently volatile and flammable, which is dangerous particularly in case of a fall or other accident involving the vehicle. Moreover, in many jurisdictions such arrangements may be prohibited by law or regulations. Further, particularly on MOPEDS, the tank extends over a considerable height, going from the steering holders to the pedal or foot rest and it is necessary to have a long length of transparent tube to display the fuel level; whereas, it would be convenient to check the level over a smaller height. Furthermore, it would be desirable that the height extent be located at a level easily accessible and visible to the user.
It is also known how to provide a device for displaying the level of liquid in a tank in which the fluid in the tank is prevented from entering the transparent tube or the like.
The above-mentioned, known device comprises a fuel tank on the inside of which is provided a pipe. This pipe is extended to bring the fuel to the carburetor. On the pipe is a tap bringing the fuel to a housing in the central part of which is mounted on a membrane preventing the passage of the fuel from the tank into the display tube. On the other side of the membrane, coming out in housing, a pipe is provided containing a liquid of a specific weight greater than that of the fuel in the tank. The volume contained in the second pipe is determined and is invariable in time. In this particular known prior art device, the membrane is relatively stiff, requiring some considerable differential to move it. In other words, a considerable subtractive factor is present.